On this day: July 1

2010: In volume, BP's Deepwater Horizon oil spill overtakes Ixtoc I, which leaked 130 million gallons off Mexico's coast from 1979 to 1980, to become the worst oceanic oil spill in U.S. recorded history. Before it was capped on July 15, 2010, the Deepwater Horizon oil spill discharged 210 million gallons of oil, making it the largest accidental marine oil spill in the history of the petroleum industry.

The Battle of Gettysburg begins, America's first zoo opens, the first Tour de France starts, the Sony Walkman hits the market, the PG-13 movie rating is introduced, and the Deepwater Horizon oil spill breaks an unfortunate record, all on this day.